A number of synthetic polymer processes involve the preparation of particulate solids as an end product which must be separated from suspending gases or vapors. With many polymeric materials this has proved to be a difficult problem since the particles in many cases either tend to be recirculated in the rapidly moving gases and are thereby lost, or, on the other hand, tend to recirculate within heated areas so that collisions occur between the particles, causing particle agglomeration and fouling of the apparatus through which they are passing. The gaseous suspensions of solids may result from many processes, but those especially contemplated here involve reaction mixtures which may comprise solutions of a polymer which are passed through contacting devices resulting in vaporization of solvents, and formation of polymeric particulate solids in suspension. In many instances this vaporization is effected by contact with high temperature vapors such as steam or hot inert gases such as nitrogen and the like.
The use of ordinary cyclones has been found unsatisfactory for separation of many polymers which tend to agglomerate as described above. The fouling of separation apparatus means that plant downtime will be required to remove deposited solids.